Shuangyang Li

Shuangyang Li

Ph.D., University of New South Wales (UNSW)

Talks and presentations

Delay-Doppler Communications: Fundamentals, Applications, and Interplay with Sensing

December 12, 2024

Tutorial (together with Prof. Weijie Yuan, Prof. Zhiqiang Wei, and Prof. Derrick Wing Kwan Ng), IEEE Global Communications Conference (GlobeCom), Cape Town, South Africa

Future vehicular networks are envisioned to support ubiquitous connectivity to a wide range of emerging applications, spanning from autonomous cars to unmanned aerial/underwater vehicles (UAV/UUV). This requires novel wireless technology to provide highly reliable data transmission and highly robust sensing simultaneously. However, the strong multipath, high delay, and Doppler features in high-mobility environments can impose great challenges for reliable wireless communications and robust sensing. Consequently, the conventional orthogonal frequency division multiplexing (OFDM) modulation may fail due to the high dynamical channel fluctuations. The recently proposed orthogonal time frequency space (OTFS) modulation has provided a fundamentally different perspective of waveform design in the delay-Doppler (DD) domain in contrast to the conventional time-frequency (TF) domain designs. Since both functionalities can be unified in the same domain, promising performance over various channels has been shown and the advantages have been widely evident from both academic and industry perspectives. This tutorial aims to provide a comprehensive understanding of the DD domain communications and sensing with specific focuses on its fundamentals, advanced designs, performance analysis, and applications. In this tutorial, we will first overview the background and fundamentals of DD domain communications and sensing. As a step further, we will introduce the state-of-the-art research progress on this topic, which consists of 4 technical parts. Finally, we will conclude the tutorial by summarizing the future directions and open problems of DD domain communications and sensing.

Delay-Doppler Domain Communications and Sensing

September 05, 2024

Tutorial Presentation, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Valencia, Spain

Future vehicular networks are envisioned to support ubiquitous connectivity to a wide range of emerging applications, spanning from autonomous cars to unmanned aerial/underwater vehicles (UAV/UUV). This requires novel wireless technology to provide highly reliable data transmission and highly robust sensing simultaneously. However, the strong multipath, high delay, and Doppler features in high-mobility environments can impose great challenges for reliable wireless communications and robust sensing. Consequently, the conventional orthogonal frequency division multiplexing (OFDM) modulation may fail due to the high dynamical channel fluctuations. The recently proposed orthogonal time frequency space (OTFS) modulation has provided a fundamentally different perspective of waveform design in the delay-Doppler (DD) domain in contrast to the conventional time-frequency (TF) domain designs. Since both functionalities can be unified in the same domain, promising performance over various channels has been shown and the advantages have been widely evident from both academic and industry perspectives. This tutorial aims to provide a comprehensive understanding of the DD domain communications and sensing with specific focuses on its fundamentals, advanced designs, performance analysis, and applications.

Delay-Doppler Domain Communications and Sensing

November 28, 2023

Presentation (together with Prof. Weijie Yuan and Prof. Zhiqiang Wei), IEEE Vitual Conference on Communications (VCC), Virtual

Future wireless networks are envisioned to support ubiquitous connectivity to a wide range of emerging applications, spanning from autonomous cars to unmanned aerial/underwater vehicles. This requires novel wireless technology to provide highly reliable data transmission and highly robust sensing simultaneously. However, the strong multipath, high delay, and Doppler features in high-mobility environments can impose great challenges for reliable wireless communications and robust sensing. Consequently, the conventional orthogonal frequency division multiplexing modulation may fail due to the high dynamical channel fluctuations. The recently proposed orthogonal time frequency space modulation has provided a fundamentally different perspective of waveform design in the delay-Doppler (DD) domain in contrast to the conventional time-frequency (TF) domain designs. Since both functionalities can be unified in the same domain, promising performance over various channels has been shown and the advantages have been widely evident from both academic and industry perspectives. This tutorial aims to provide a comprehensive understanding of the DD domain communications and sensing with specific focuses on its fundamentals, advanced designs, performance analysis, and applications. In this tutorial, we will first overview the background and fundamentals of DD communications and sensing. As a step further, we will introduce the state-of-the-art research progress on this topic, which consists of 3 technical parts: 1) Fundamentals of DD domain communications, 2) Recent advances of DD domain multiple-input multiple-output (MIMO) communications, and 3) DD domain communications with integrated sensing functionality. Finally, we will conclude the tutorial by summarizing the future directions and open problems of DD domain communications and sensing.

ISAC-assisted Delay Doppler Communications in Vehicular Networks

July 12, 2023

Presentation (together with Prof. Weijie Yuan and Prof. Zhiqiang Wei), IEEE Signal Processing Society Webinar 2023, Virtual

Orthogonal time frequency space (OTFS) modulation, which relies on delay Doppler domain for communications, is a promising candidate for supporting reliable information transmission in high-mobility vehicular networks. In this talk, we will provide a general framework for integrated (radar) sensing and communication (ISAC) technique for assisting delay Doppler communications, including both uplink and downlink vehicular communication systems. Benefiting from the OTFS-ISAC signals, the roadside unit (RSU) is capable of simultaneously transmitting downlink information to the vehicles and estimating the sensing parameters of vehicles, e.g., locations and speeds, based on the reflected echoes. Then, relying on the estimated kinematic parameters of vehicles, the RSU can construct the topology of the vehicular network that enables the prediction of the vehicle stated in the following time instant. Consequently, the RSU can effectively formulate the transmit downlink beamformers according to the predicted parameters to counteract the channel adversity such that the vehicles can directly detect the information without the need of performing channel estimation. As for the uplink transmission, the RSU can infer the delays and Dopplers associated with different channel paths based on the aforementioned dynamic topology of the vehicular network. Thus, inserting guard space as in conventional methods are not needed for uplink channel estimation which removes the required training overhead.

Delay-Doppler Domain Communications and Sensing

June 01, 2023

Presentation (together with Prof. Weijie Yuan and Prof. Zhiqiang Wei), IEEE International Communications Conference (ICC), Rome, Italy

Future wireless networks are envisioned to support ubiquitous connectivity to a wide range of emerging applications operating in hostile environments, spanning from autonomous cars to unmanned aerial/underwater vehicles (UAV/UUV), and low-earth-orbit (LEO) satellites, etc. This requires novel wireless technology to provide highly reliable data transmission and highly accurate sensing simultaneously. However, the strong multipath, high delay and Doppler features in those hostile environments can impose great challenges for reliable wireless communications and accurate sensing. Consequently, the conventional orthogonal frequency division multiplexing (OFDM) modulation may fail due to the high dynamical channel fluctuations and complex sensing scenario. The recently proposed orthogonal time frequency space (OTFS) modulation has provided a fundamentally different perspective of waveform design in the delay-Doppler (DD) domain in contrast to the conventional time-frequency (TF) domain designs. The DD domain communications and sensing have shown promising performance over various channels thanks to the intrinsic connections between the two functionalities in the DD domain and its advantages have been widely evident from both academic and industry perspectives. This tutorial aims to provide a comprehensive understanding of the DD domain communications and sensing with specific focuses on its fundamentals, advanced designs, performance analysis, and applications.

Orthogonal Time Frequency Space Modulation: Waveform for Future Wireless Networks

June 19, 2022

Presentation (together with Prof. Weijie Yuan and Prof. Zhiqiang Wei), IEEE Vehicular Technology Conference (VTC) Spring 2022, Helsinki, Finland (virtual)

Future wireless networks are expected to support ubiquitous connectivity to a wide range of emerging applications operating in hostile environments, spanning from autonomous cars to low-earth-orbit satellites, and underwater acoustic communications. The strong multipath, high delay and Doppler features in those hostile environments can impose great challenges for reliable wireless communications. Consequently, the conventional OFDM modulation may fail due to the high dynamical channel fluctuations. Recently proposed orthogonal time frequency space (OTFS) modulation has provided a different perspective of waveform design in contrast to the time-frequency signal processing paradigm. OTFS has shown promising performance over various channels and its advantages has been widely evident from both academic and industry perspectives. This tutorial aims to provide the state-of-art of OTFS with specific focuses on its fundamentals, advanced designs, performance analysis, and applications.

Delay-Doppler Domain Signal Processing for Communication: Why It is Good?

December 14, 2021

Presentation, Southern University of Science and Technology, Shenzhen, China

The recently proposed orthogonal time frequency space (OTFS) modulation has provided a new perspective for communication designs for future wireless systems. In contrast to conventional multi-carrier modulation schemes, OTFS modulation innovatively multiplexes the information data in the delay-Doppler (DD) domain rather than the well-known time-frequency (TF) domain. Thus, it provides many appealing advantages for communication designs, such as potential full-diversity and low-complexity transmitter/receiver implementation. In this talk, we will present the recent advances of DD domain signal processing for communications and discuss the reasons why it is good. In specific, this talk will cover several developments of OTFS modulation from different perspectives, including the achievable rate analysis, channel coding, cross domain detection, multi-user MIMO design, and integrated sensing and communications (ISAC), where important insights on DD domain communication designs will also be highlighted.

Recent Advances on OTFS Modulation: Performance Analysis and Signal Detection

June 04, 2021

Presentation, Xidian University, Xi'an, China

Orthogonal time frequency space (OTFS) modulation has attracted substantial attention recently. It has demonstrated superior performance compared to the conventional orthogonal frequency-division multiplexing (OFDM) modulation in the high-Doppler scenarios. Therefore, it has been widely acknowledged as a potential key enabler for emerging applications, such as unmanned aerial vehicles (UAVs) and low-earth-orbit (LEO) satellites. In this presentation, we will summarize some recent advances on OTFS modulation, with a specific focus on its performance analysis with channel coding and signal detection. In particular, we will unveil the trade-off between the coding gain and diversity gain for OTFS modulation. We will also discuss how the unitary transformations between different domains, such as the time-delay domain and the delay-Doppler domain, can help the signal detection.